Most of the discussions I have heard about Photos, both for iOS and for MacOS, lean towards discussing its use as a photo cataloging and organizing file system. There has been very little discussion about its image-processing and manipulation capabilities.

Since I have been taking photos since 1958, I'm quite capable of keeping my image collection organized; I really only want software for tweaking, editing, manipulating the images (doing my "darkroom work"). Pixelmator works very well. Can Photos do everything Pixelmator can? Can Pixelmator do everything Photos can (in terms of image manipulation)?